Agriculture is considered on e of the nations most hazardous occupations with an estimated death rate of 21 per 100,000 workers in 1996. Many of these fatalities are due to tractor overturns. A review of agricultural fatalities concluded that "tractor overturns (are) the leading cause of occupational traumatic death in the U.S. agricultural industry." Tractor rollover fatalities have been called an "occupational obscenity" by NIOSH (National Institute for Occupational Safety and Health) Director J. Donald Millar (NIOSH 1993). A rollover protective structure (ROPS), as described in ASAE S519, is a protective structure designed to minimize the frequency and severity of operator injury resulting form accidental tractor upset. RPS utilization has shown to have dramatic impacts in reducing fatalities during vehicle overturns. The overall objective of this project is to investigate and evaluate ROPS designs for agricultural tractors in the United States to provide operator protection on tractors and in operating conditions not currently available. The specific objectives include: developing an inventory of agricultural tractor ROPS availability (specifically for older tractors); prioritizing the agricultural tractor population for ROPS design feasibility; design, construction, and testing of ROPS for the two highest prioritized pre-ROPS tractors; conducting axle housing strength tests; conducting field upset tests on the NIOSH auto-ROPS; evaluating false deployment possibilities of the auto-ROPS; and presenting pre-ROPS tractor ROPS and auto-ROPS design and test results to commercial ROPS manufacturers for commercial construction and follow-up field testing.